Dynamic double-circuit in-line heater

Abstract

A dynamic double-circuit in-Line heater is disclosed, as well as a machine containing the heater and a method of operating the machine.

The invention claimed is: 
     
       1. A method for controlling a heater for a liquid food or beverage preparation machine, the liquid being circulated through the heater for brewing a food or beverage ingredient, the heater comprising: a body having an inlet, an outlet and a heating chamber extending therebetween, the inlet, outlet and heating chamber forming together a rigid passage for guiding the liquid circulating through the body; and a heater cooperating with the body for supplying heat into the heating chamber; and
 the heater comprises (i) at least two different types of heating elements selected from the group consisting of a thick film, a surface heating element, a heating cartridge selected from the group consisting of a cylindrical heating cartridge and a wrapped heating cartridge, and combinations thereof; and (ii) at least two electrical control circuits for independently activating and deactivating each heating element, wherein the heating elements are independently activated or deactivated comprising: 
 switching on and off the electrical control circuits, so as to avoid simultaneous switching on or off of both heating elements, wherein one or both of the heating elements are in direct contact with the body to enable heat to be conducted directly between the heating elements and the body. 
 
     
     
       2. The method of  claim 1 , wherein the step of switching on the electrical control circuits heats the liquid from a tap temperature of 10 to 30° C. to a brewing temperature of 80 to 100° C. 
     
     
       3. The method of  claim 1 , wherein the step of switching on the electrical control circuits heats the liquid from 20° C. to 90° C. in a heat up time of below 20 seconds. 
     
     
       4. The method of  claim 1 , wherein the heating power of each heating element is substantially identical. 
     
     
       5. The method of  claim 1 , wherein the heater comprises a resistive heater, the resistive heater comprising at least two resistive heating circuits, adapted to be coupled to the electrical control circuits. 
     
     
       6. The method of  claim 5 , wherein the resistive heater is a thick film printed on an inox plate which is soldered to the body.